Largest dimensions possible to send out on a g-code file without tiling?

I think if you change $130 and $131 to the new size, you should be good.Perhaps go through set up and select a different machine?
GRBL_Settings_Pocket_Guide_Rev_B.pdf

[new feature] Larger work area support - Easel - Easel Community Forum

I did it and the gcode came out when I downloaded it.